Project description:Cell type-specific master transcription factors (MTFs) play vital roles in defining cell identity and function. However, the roles ubiquitous factors play in the specification of cell identity remain underappreciated. Here we show that all three subunits of the ubiquitous heterotrimeric CCAAT-binding NF-Y complex are required for the maintenance of embryonic stem cell (ESC) identity, and establish NF-Y as a novel component of the core pluripotency network. Genome-wide occupancy and transcriptomic analyses in ESCs and neurons reveal that not only does NF-Y regulate genes with housekeeping functions through cell type-invariant promoter-proximal binding, but also genes required for cell identity by binding to cell type-specific enhancers with MTFs. Mechanistically, NF-Y's distinctive DNA-binding mode promotes MTF binding at enhancers by facilitating a permissive chromatin conformation. Our studies unearth a novel function for NF-Y in promoting chromatin accessibility, and suggest that other proteins with analogous structural and DNA-binding properties may function in similar ways. Genome-wide mapping of NF-YA, NF-YB, and NF-YC subunits of the NF-Y complex in mouse ESCs, and microarray gene expression profiling of control knockdown (KD), NF-YA KD, NF-YB KD, NF-YC KD, and NF-YA/NF-YB/NF-YC triple KD ESCs.
Project description:Cell type-specific master transcription factors (MTFs) play vital roles in defining cell identity and function. However, the roles ubiquitous factors play in the specification of cell identity remain underappreciated. Here we show that all three subunits of the ubiquitous heterotrimeric CCAAT-binding NF-Y complex are required for the maintenance of embryonic stem cell (ESC) identity, and establish NF-Y as a novel component of the core pluripotency network. Genome-wide occupancy and transcriptomic analyses in ESCs and neurons reveal that not only does NF-Y regulate genes with housekeeping functions through cell type-invariant promoter-proximal binding, but also genes required for cell identity by binding to cell type-specific enhancers with MTFs. Mechanistically, NF-Y's distinctive DNA-binding mode promotes MTF binding at enhancers by facilitating a permissive chromatin conformation. Our studies unearth a novel function for NF-Y in promoting chromatin accessibility, and suggest that other proteins with analogous structural and DNA-binding properties may function in similar ways. Genome-wide mapping of NF-YA, NF-YB, and NF-YC subunits of the NF-Y complex in mouse ESCs, and microarray gene expression profiling of control knockdown (KD), NF-YA KD, NF-YB KD, NF-YC KD, and NF-YA/NF-YB/NF-YC triple KD ESCs.
Project description:Transcriptional control is dependent on a vast network of epigenetic modifications. One epigenetic mark of particular interest is tri-methylation of lysine 27 on histone H3 (H3K27me3), which is catalyzed and maintained by the Polycomb Repressor Complex (PRC2). Although this histone mark is studied widely, the precise relationship between its local pattern of enrichment and regulation of gene expression is currently unclear. We have used ChIP-seq to generate genome wide maps of H3K27me3 enrichment, and have identified three enrichment profiles with distinct regulatory consequences. First, a broad domain of H3K27me3 enrichment across the body of genes corresponds to the canonical view of H3K27me3 as inhibitory to transcription. Second, a peak of enrichment around the transcription start site is commonly associated with â??bivalentâ?? genes, where H3K4me3 also marks the TSS. Finally and most surprisingly, we identified an enrichment profile with a peak in the promoter of genes that is associated with active transcription. Genes with each of these three profiles were found in different proportions in each of the cell types studied. The data analysis techniques developed here will be useful for the identification of common enrichment profiles for other histone modifications that have important consequences for transcriptional regulation. Genomic DNA was extracted from ES cells and G1ME cells in mouse. ChIP-seq with antibodies for H3K27me3, RNApol-II were run for both cell types. As a control, whole cell extract or Input DNA was also sequenced for both cell types without the inclusion of an antibody.
Project description:This SuperSeries is composed of the following subset Series: GSE27967: ChIP-seq analysis reveals distinct H3K27me3 profiles associated with gene regulation [ChIP-seq] GSE27969: ChIP-seq analysis reveals distinct H3K27me3 profiles associated with gene regulation [mRNA profiling] Refer to individual Series
Project description:Transcriptional regulation of developmentally controlled genes is at the heart of differentiation and organogenesis. In this study, we have performed global genomic analyses in murine embryonic stem (ES) cells and in human cells in response to activation signals. We have identified an essential role for the ELL/P-TEFbcontaining Super Elongation Complex (SEC) in the regulation of gene expression including several genes bearing paused RNA polymerase II (Pol II). Paused Pol II has been proposed to be associated with loci that respond rapidly to environmental stimuli. However, our studies in ES cells have also identified a requirement for SEC at genes without preloaded Pol II, which also respond dynamically to differentiation signals. Our findings suggest that SEC is a major class of active P-TEFb-containing complexes required for transcriptional activation in response to environmental cues such as differentiation signals. Examination of ELL2, AFF4, and Pol II before and after activation signals in two cell types.
Project description:We use ChIP-Seq and RNA-Seq technology to profile the H3K9me2 modification and transcription under different conditions of GLP activity. GLP and G9a are major H3K9 dimethylases, and are essential for mouse early embryonic development. Here we report that GLP and G9a possess intrinsic histone methylation propagating activities. The histone methyltransferase activities of GLP and G9a are stimulated by neighboring nucleosomes pre-methylated at H3K9. These stimulation events function in cis and are dependent on H3K9 methylation binding activities of ankyrin repeats domains in GLP and G9a. In mouse embryonic stem cells (ESCs) harboring a mutant GLP lacking H3K9 methylation propagating activity, pluripotent genes display a delayed kinetics in establishing H3K9 methylation and gene silencing during differentiation. Disruption of the H3K9 methylation propagating activity of GLP in mice causes growth retardation of the embryos, ossification defects of calvaria and early postnatal lethality. We propose that GLP¡¯s ability to rapidly propagate H3K9 methylation is required for efficient gene silencing during programmed cell fate transition. H3K9me2 and H3K9me1 are ChIPped and sequenced in WT mESC and GLP-mutant mESCs, and RNA-Seq was done for those cells as well.
Project description:Polycomb Repressive Complex 1 and histone H2A ubiquitination (ubH2A) contribute to embryonic stem cell (ESC) pluripotency by repressing lineage-specific gene expression. However, whether active deubiquitination co-regulates ubH2A levels in ESCs and during differentiation is not known. Here, we report that the histone H2A deubiquitinase Usp16 regulates H2A deubiquitination and gene expression in ESCs, and importantly, is required for ESC differentiation. Usp16 knockout is embryonic lethal in mice, but does not affect ESC viability or identity. Usp16 binds to the promoter regions of a large number of genes in ESCs and Usp16 binding is inversely correlated with ubH2A levels and positively correlated with gene expression levels. Intriguingly, Usp16-/- ESCs fail to differentiate due to ubH2A-mediated repression of lineage-specific genes. Finally, Usp16, but not the enzymatically inactive mutant, rescues the differentiation defects of Usp16-/- ESCs. Therefore, this study identifies Usp16 and H2A deubiquitination as critical regulators of ESC gene expression and differentiation. Examination of binding pattern of H2A deubiquitinase Usp16 and ubH2A in mouse embryonic stem cells and embroid bodies
Project description:Nucleoporins (Nups) are a family of proteins best known as the constituent building blocks of nuclear pore complexes (NPCs), the transport channels that mediate nuclear transport. Recent evidence suggest that several Nups have additional roles in controlling the activation and silencing of developmental genes, however, the mechanistic details of these functions remain poorly understood. Here, we show that depletion of Nup153 in mouse embryonic stem cells (mESCs) causes the de-repression of developmental genes and induction of early differentiation. This loss of pluripotency is not associated with defects in global nucleo-cytoplasmic transport activity. Instead, Nup153 binds to the transcriptional start site (TSS) of developmental genes and mediates the recruitment of the polycomb repressive complex 1 (PRC1) to its target loci. Our results reveal a nuclear transport-independent role of Nup153 in maintaining stem cell pluripotency and introduce a role of NPC proteins in mammalian epigenetic gene silencing. RNA-seq, ChIP-Seq, and DamID-Seq for Nup153, Oct4, and key chromatin regulators in mouse ES cells and neural progenitors
Project description:Chromatin modifications have been implicated in the self-renewal and differentiation of embryonic stem cells (ESCs). However, the function of histone variant H2A.Z in ESCs remains unclear. We show that H2A.Z is highly enriched at promoters and enhancers and is required for both efficient self-renewal and differentiation of murine ESCs. H2A.Z deposition leads to an abnormal nucleosome structure, decreased nucleosome occupancy and increased chromatin accessibility. In self-renewing ESCs, knockdown of H2A.Z compromises OCT4 binding to its target genes and leads to decreased binding of MLL complexes to active genes and of PRC2 complex to repressed genes in self-renewal of ESCs. During differentiation of ESCs, inhibition of H2A.Z also compromises RA-induced RARα binding, activation of differentiation markers and the repression of pluripotency genes. We propose that H2A.Z mediates such contrasting activities by acting as a 'general facilitator' that generates access for a variety of complexes both activating and repressive. ChIP-Seq in murine embryonic stem (mES) cells for H2A.Z and acetylated H2A.Z. ChIP-Seq of H3K4me3, H3K27me3, RbBP5, SUZ12 and OCT4 for mES cells of both H2A.Z RNAi knockdown and shLuc control. ChIP-Seq of RARalpha in H2A.Z knockdown (withdraw of LIF and exposure to RA for 3h) and control cells. MNase-Seq and chromatin accessibility assay using Benzonase digestion followed by next-generation sequencing for mES cells of both H2A.Z RNAi knockdown and shLuc control. ChIP-Seq of H2A.Z and H3K4me3 for mES cells of both MLL4 RNAi knockdown and shLuc control. RNA-Seq for mES cells of H2A.Z knockdown and shluc control. RNA-Seq for embryonic bodies derived from mES cells (H2A.Z knockdown and shLuc control) at day 3 and day 7.